Charles t



176 Model. I 4

C. T. SNEDEKOR. ELECTRIC CONDUCTOR.

'I'NE iwmus nuns co., mow-mum, msumawn o c conductors as now ordinarily insulated and art to which my invention belongs to make UNITED STATES PATENT OFFICE.

CHARLES T. SNEDEKOR, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO THE WASI-IBURN & MOEN MANUFACTURING COMPANY, OF SAME PLACE.

ELECTRIC CONDUCTOR.

SPECIFICATION forming part of Letters Patent No. 477,787, dated June 28, 1892.

Application filed October 17,1891.

To all whom it may concern.-

Be it known that 1, CHARLES T. SNEDEKOR, acitizen of the United States of America, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Insulating Electric Conductors; and Ido hereby declare that the following is a full, clear, and exact description thereof,'which, in connection with the drawings making a part of this specificatiomwill enable others skilled in the and use the same.

My invention relates to insulating electric conductors; and the object of my invention is to improve upon the insulation of electric to produce an absolutely safe insulation; and my invention consists in my improved insulation of electric conductors, and more particularly in making an insulated conductor which has a fire-proof covering or coating applied directly to the wire or cable, and a covering or coating made of rubber, gutta-percha, or the compounds thereof, and forming a seamless tube applied directly to the fireproof coating and a second fire-proof coating applied directly to the rubber or gutta-percha coating, as will be hereinafter fully described." In the ordinary method of insulating electric conductors a coating or covering of rubber or gutta-percha or the compounds thereof is applied directly to the wire or cable forming the conductor to insulate the same. Said coating or covering is a most reliable insulating covering forthe conduct-or, but said covering is easily ignited either from external heat or from an overheated conductor and is the direct cause of fires and great damage thereby. In the ordinary insulation of electric conductors by means of a coating or covering of rubber, gutta-percha, or the compounds thereof applied directly to the metallic conductor there is nothing to prevent said coating or covering from becoming ignited either from internal heat from the conductor itself or from external heat. In my improved insulation of electric conductors I employ the ordinary coating or covering of rubber, guttapercha, or the compounds thereof, the same forming a seamless tube, which is the best Serial No. 409,052. (No model.)

known insulation for a metallic conductor, and in addition to the rubber coating I employ two other coatings or coverings of refractory or fire-proof material, one applied directly to the wire, cable, or other metallic conductor and the other applied directly to the rubber or gutta-percha covering.

Referring to the drawings, Figure 1 is a longitudinal view of my improved insulated con- 6 o ductor, showing the different coatings partially broken away; and Fig. 2 is a cross-section on line 2 2, Fig. 1.

In carrying out my invention a refractory or fire-proof coating 2, preferably consisting of acompound of calcined magnesia,one part, and china-clay, one part, mixed in silicate of soda, one part, is applied directly to the wire, cable, or other conductor 1, and when sufliciently hardened and smoothed is covered with a coating 3 preferably consisting of a compound of rubber applied directly over said refractory or fire-proof coating 2 and forming a seamless tube of rubber, gutta-percha, or the compounds thereof covering the same, and directly upon said coating of rubber 3 a second refractory or fire-proof coating 4, consisting of the compound above described, is applied.

The refractory or fire-proof compounds 2 and at may have combined therewith asbestos and mica, if preferred, one part each.

By my improved insulation of electric conductors I render the ordinary insulating coating, made of rubber, gutta-percha, or the compounds thereof, fire-proof both from internal and external heat, and thus produce an absolutely safe insulation of the electric conductor.

- In my improved insulation of electric conductors less rubber, gutta-percha, or thecompounds thereof is used to form the rubber 9o coating between the fire-proof coatings than is ordinarily used in the insulation of electric conductors, and the fire-proof coating over said rubber coating will protect the same from wear and abrasion.

By employing a coating of rubber orguttapercha or the compounds thereof I am onabled to form a seamless tube applied directly over the fire-proof coating without the intervention of any fibrous covering, thus saving Ico considerable cost in the manufacture of the insulated electric conductor and at the same time employing the best form of insulating coating to produce an absolute insulation of the electric conductor.

It will be understood that I do not limit myself to the particular substances above set forth or the proportions thereof from which to make the refractory or lire-proof coatings, as any equivalent substances may be used which will produce the same result.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an insulated electric conductor, the combination, with a metallic conductor, of a fire-proof compound consisting of calcined magnesia, china-clay, and silicate of soda applied to the metallic conductor, of a coating 2 consisting of a compound of rubber applied to said fire-proof compound and a second fire proof com-pound applied directly to said rubber compound, substantially as set forth.

2. The combination, with a metallic electric conductor, of means for insulating the same,

7 consisting of, first, a fire-proof compound of calcined magnesia and silicate of soda applied directly to the metallic conductor; second, a compound of rubber applied directly' to the first-mentioned fire-proof compound, and, third, said fire-proof compound applied directly to said compound of rubber, substantially as set forth.

CHARLES T. SNEDEKOR.

Witnesses:

JOHN C. DEWEY, KATIE FARRELL. 

